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Broad band transmission system

  • US 5,768,279 A
  • Filed: 01/25/1994
  • Issued: 06/16/1998
  • Est. Priority Date: 01/25/1994
  • Status: Expired due to Term
First Claim
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1. A digital broad band transmission system for sending downstream broad band data and telephone signals from a central office to a number of subscriber set top terminals and to carry upstream control signals and telephone signals from each set top terminal to the central office, the digital broad band transmission system comprising:

  • (a) a marking circuit in the central office operative to mark each frame of data to indicate the set top terminals it is to be received by;

    (b) a downstream and upstream optical fiber between the central office and a telephone distribution box proximate a plurality of said set top terminals, said downstream optical fiber coupled to said marking circuit;

    (c) a telephone signal and data transmitter located in the central office and coupled to said downstream optical fiber and operative to transmit said frames of data and telephone signals along said downstream optical fiber to said telephone distribution box and for receiving upstream telephone and control light signals transmitted from said telephone distribution box along the upstream optical fiber to the central office;

    (d) a control signal receiver in said central office coupled to the upstream optical fiber;

    (e) an opto-electric converter located in said telephone distribution box and coupled to said downstream optical fiber so as to convert the light signals from said downstream optical fiber to electrical signals and coupled to said upstream optical fiber so as to convert electrical signals from the set top terminal to upstream light signals;

    (f) a plurality of telephone drop lines coupled to said telephone distribution box at one end and coupled at another end thereof to respective ones of said plurality of set top terminals, each telephone drop line made up of one or more twisted pairs of conductors, said telephone drop lines operative to conduct said downstream electrical signals to said set top terminals;

    (g) a telephone and control signal transmitter in said set top terminal operative to transmit telephone and control signals along said telephone drop lines to said to opto-electric converter for conversion to upstream telephone and control light signals;

    wherein said downstream data is broadcast on ones of said twisted pairs in a single broad frequency band in a frequency range starting above a data frequency threshold of 1 megahertz, telephone signals are transmitted from the central office via said telephone distribution box to the set top terminals and from the set top terminals to the central office via said telephone distribution box in a distinct telephone signal frequency band below the data frequency threshold, and upstream control signals are transmitted from the set top terminals via said telephone distribution box to the central office, in a distinct control signal frequency band above said telephone signal frequency band, the control signal frequency band having an upper limit no greater than the data frequency threshold, andwherein the telephone signal and data transmitter and said telephone and control signal transmitter each output signals that are shaped so that a power versus frequency curve is weighted towards the lower frequencies and power drops to zero at zero frequency.

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